TY JOUR TI FORECASTING OF THE RESIDUAL LIFE OF METAL BEAMS SUB-CRANE OF INDUSTRIAL BUILDINGS OF LONG SERVICE LIFE KW industrial safety KW residual life KW physical wear KW crane girder KW damage KW technical condition category JO Bulletin of Belgorod State Technological University named after. V. G. Shukhov AU Markeev, V.S. AU Borkov, P.V. PY 2021 IS 6 PB Belgorod State Technological University named after V.G. Shukhov